Plunge-type routers are well known and commonly used to cut grooves, edges and a variety of shapes in work pieces made of wood and other materials. The shapes are determined by the kind and shape of router bits used, the depth of cut of the bit and the path of travel by the router bit relative to the work piece. A plunge router is constructed to move the router bit toward and away from the work piece when the router is being operated in a freehand manner. It can often also be mounted to a router table so that the router bit extends through an opening in the top of the table. The depth of cut of the router bit is typically determined by an adjustable depth stop system which may or may not include means for locking the router in its plunged position.
During freehand operation, the plunge router may be supported on the work piece with the bit retracted and placed in the desired location so that when it is turned on and plunged downwardly, the router bit advances into the work piece and the operator then moves it relative to the work piece to complete the desired routing operation. To do the plunging operation, the operator must exert a downward force on the motor housing assembly, generally by pressing on attached handles to move the router bit into contact with the work piece. The motor housing assembly is typically biased to automatically retract the router bit from the work piece when the downward force imparted by the operator is removed.
Plunge routers generally include a plunge adjustment mechanism that enables the operator to control the distance the router bit can move toward the work piece and thereby determine its depth of cut. As is well known to those who have used plunge type routers, the adjustment of the stop system must be carefully done to achieve the desired depth of cut. Because the type and size of various router bits are very different, it is prudent if not necessary to recalibrate or reset the adjustment means after any manipulation of the router bit to insure that it has been accurately set to achieve the desired depth of cut. There are many other devices that attempt to accurately set the depth adjustable stop to provide an accurate depth of cut, including adjustable rods, scales with indicators, micrometer type adjusters and other systems. Such adjustable stop mechanisms in the prior art are generally hand manipulated and some may have a printed scale or other indicia located on the mechanism for use in providing a specified depth of cut. However, it is still necessary for users to carefully measure the depth of cut in one way or another to insure that the desired cut will be made. In this regard, it is often common practice to perform a test cut on a scrap piece and actually measure the result and to iteratively adjust the stop mechanism until the proper result is achieved.